New subwoofer Stack

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jakkle21
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Joined: Sat Oct 30, 2021 1:47 pm
Location: Flagstaff AZ

New subwoofer Stack

#1 Post by jakkle21 »

Hello All
I'm the sound tech, for a small art-group in northern Arizona.
I got serious about upgrading our system and learning more about running it about a year ago and quick came across this forum. I've been impressed with the knowledge and the designs ever since.
I finally got to a point where I can start thinking about building out a new subwoofer array and I want some advice on which ones to go with.
Pack size is not really an issue, I can transport as much as I need to, but I prefer scalability and ease of transport.
The system will be used primarily outside and off of generators.
I have a berhinger erurocack mixer, and a driverack pa+.
My current tops are 4x JBL eon-15P
I have a Crown XLS 1500, running 2 15" 1000w Walmart subs in 24" square boxes.
Then I just bought a stack of Crown Micro-techs
I have 1x 1200 and 4x 2400 as well as 2x Macro-tech 2400
What Ive been thinking is to build 8 max width T45s.
Would the xls 1500 be able to run 4 of them? Would 1 MT2400 run all 8? Not at war-volume.
Then as time/budged allows, I'd like to build 4 more subs and replace my tops with probable 4-6 DR250s.
We do play enough weird bass music to want the system to get down as low as is reasonable, which is why I was leaning towards the Tubas over the Titans. So that I could still get really low with only a few boxes, instead of the whole array.
I'm very open to changing all of my plans though, I'm still very early in my build and I have to save up before I can buy any wood or speakers.
I just received my plans last week and I'm very excited to at least be thinking about the nex (first?) step.
P.s. I showed my roommate the plans for the truck-tuba this morning and he said it was the nicest looking truck sub design he had ever seen. Good Job Bill!

Grant Bunter
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Re: New subwoofer Stack

#2 Post by Grant Bunter »

Hi and welcome :)

Subs decisions are always about the content to be played by them, and any compromises you may live with.
Do you happen to have measured the bass frequencies in the music you play?
You can work out content with Audacity.
That will aid you in your decision.

If it turns out that 30Hz is acceptable, as long as you always use at least 4 x T45's, then, that's a good choice.
You see, horn subs don't complain if you push them to hard, they just blow drivers.
Part of having a Driverack is being able to use the limiter function to protect your drivers, so, even if an amplifier isn't capable of putting out enough power, doesn't mean it can't produce transients that will blow drivers. You always need to engage the limiter!

The XLS1500 is capable of 45V at 4 ohms (or 2 cabs per channel), which won't take the cabs to full power with the 3012lf or the lab12.
The macrotech 2400 will do 65V/channel with 1 cab, or 2 cabs/4 ohms/56V, just enough for 2 cabs per channel to full power with the 3012lf or the lab 12.

Think long and hard about the generator you will use and it's specs. It will need enough power to keep up with transient sags in the power amps, particularly on the subs.

How many cabs is enough? Adding 4 more after your initial 8 would only add an extra 3dB in output, which is not a lot, just noticeably louder.

At the moment, ply prices and driver availability (Eminence are plugging away at getting back up to speed post covid, and are working their way through backorders) are certainly factors in you being able to complete your initial goal.

You haven't told us if you're a competent wood worker with plenty of tools. Where are you at with that?

Hope this helps get you on your way...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

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Seth
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Re: New subwoofer Stack

#3 Post by Seth »

It's my opinion that if you're primarily outdoors, Titan's are hands down the better choice. Four full width T48's will, by far, outperform 8 full width T45's outdoors, no matter the low frequency extension of the intended content. It would take 19 full width T45's loaded with 3012LF's to match the output potential of 4 full width, v-plated, T48's loaded with 3015LF's at 40Hz. Outdoors, Titan is king.

I'd completely recommend you start with 4 Full width, 3015LF loaded, T48's... as long as you're able to transport something that size.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Tom Smit
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Location: Sarnia, Ont. Canada

Re: New subwoofer Stack

#4 Post by Tom Smit »

jakkle21, welcome to the forum!

As Grant has suggested, check out how low the frequencies are in the music that you reproduce. Not only how low, but, how often.
As Seth has posted, T48 may be a better option. Clusters of them reach 35hz!
TomS

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Seth
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Re: New subwoofer Stack

#5 Post by Seth »

Another perspective on the comparison; 4 full width T48's loaded with 3015LF's would need less than 100 watts per cab (79 watts each, to be specific) to match 8, full width, 3012LF loaded T45's at full power on the limiter.

That's 316 total combined watts into 4 T48's, to match 2500 total combined watts into 8 T45's.

Worth heavy consideration when running off a generator.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Seth
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Re: New subwoofer Stack

#6 Post by Seth »

Tom Smit wrote: Sat Aug 13, 2022 11:56 pm As Seth has posted, T48 may be a better option. Clusters of them reach 35hz!
Indeed :thumbsup: Even high passed at 35Hz, they'll still have usable output and noticeable energy in the 25-30Hz region.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

jakkle21
Posts: 13
Joined: Sat Oct 30, 2021 1:47 pm
Location: Flagstaff AZ

Re: New subwoofer Stack

#7 Post by jakkle21 »

Thank you for all the replies.

Are the limits listed in the plans somewhere? I haven't read them very in-depth yet. I probably should have before making my first post.

I have a very skilled builder, with a well stocked wood-shop. I'm fairly competant myself, but luckily I've got someone much better to handle that.

I know most of the speakers are back ordered right now and that wood is expent and scarce. I'm not in a rush to get this system built quickly. It will take me some time to save up the funds for the next step. I'm just excited to be in the planning stage now.

I have an inverter generator that can run the Xls and the jbls at full blast, no problem. I plan on getting a second, to run in parallel, when I'm able. I will borrow or rent a big generator for anything that requires 2 or more of the 2400s. Unless I'm somewhere that has great electrical already. Sizing and building good power distribution for the system is part of what I'm figuring out right now. I know I need to run 20a wiring for the 2400s

When I needed I crossover for my pa, I bought the driverack because these forums recommended it for use as a limiter. So I understand the importance of doing that correcttly. I don't want to have to buy any speakers twice. I wouldnt say I'm good at using it yet, but I'm comfortable with it and know my way around it's menus and the manual.

I've only analyzed a few songs so far, and 35hz should be enough. I'm just trying to do a bit of reasonable over-building. I need to analyze more and see how many actually go any lower than that, which I know isn't going to be many. But we do play lots of weird bass heavy electronic music, in lossless formats.

Titans vs Tubas is something I keep going back and forth on, but if I'm understanding the math right, I could easily run 4 Titans off the xls at much higher levels than I could the Tubas. Or 8 off one 2400. If that math is correct, I think that's a no brainer. Maybe I'd aim for building 2 first, which won't get as low, but then I could get more comfortable running them, and get everyone else excited about building the rest.

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Seth
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Re: New subwoofer Stack

#8 Post by Seth »

jakkle21 wrote: Sun Aug 14, 2022 3:18 pm Are the limits listed in the plans somewhere?..

I know most of the speakers are back ordered right now...

I have an inverter generator that can run the Xls and the jbls at full blast, no problem...

Titans vs Tubas...
Yes, the limiting recommendations for the Titans and Tubas are in the plans.

Parts Express is currently out of stock on 3015LF's, but Amazon is showing 3 in stock

Not sure what generator you have, but if it ends up being a limiting factor, you can likely run a pair of Titans on one channel and your tops on the other channel of your XLS in a pinch and still cover a decent space with great sound. T48's maximum output would be down about 2½-3dB with that amp compared to the 2400's. Obviously, it would really be ideal if you had the Titans on one of the 2400's, one cab per amp channel (T48 voltage limit is 60v with the 3015LF). Which, if you're just running one cab per amp channel, you wont need a 20A circuit for. A standard 15 amp circuit will be fine. Depending on your generator, it may (or may not) be enough for both amps. I wouldn't recommend running 2 Titans per amp channel on any of the 2400's unless you have to. The power available into a 4Ω load is less than what the cabs can use. Wouldn't be the end of the world. Just wouldn't be ideal.

Starting with 2 isn't a bad idea. And yes, Titans on the XLS will outperform Tubas on the XLS. I'm not sure what your end game is in this endeavor, but you may just find that 2 is enough. It's likely going to be the equivalent of 10 or more of the Walmart subs you're using now.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Strange Kevin
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Location: Scottsdale AZ

Re: New subwoofer Stack

#9 Post by Strange Kevin »

Hi Jakkle,

Fellow AZ here. (PHX)

I'd also probably vote T48's.

If your ever in the Tucson area, ACUA here on the Fourms has a small herd of Tuba 45's.
You may wanna reach out and get his opinion.

Welcome aboard!

overdoseonmekka
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Location: Miami, FL

Re: New subwoofer Stack

#10 Post by overdoseonmekka »

Seth wrote: Sun Aug 14, 2022 5:07 pm
jakkle21 wrote: Sun Aug 14, 2022 3:18 pm Are the limits listed in the plans somewhere?..

I know most of the speakers are back ordered right now...

I have an inverter generator that can run the Xls and the jbls at full blast, no problem...

Titans vs Tubas...
Yes, the limiting recommendations for the Titans and Tubas are in the plans.

Parts Express is currently out of stock on 3015LF's, but Amazon is showing 3 in stock

Not sure what generator you have, but if it ends up being a limiting factor, you can likely run a pair of Titans on one channel and your tops on the other channel of your XLS in a pinch and still cover a decent space with great sound. T48's maximum output would be down about 2½-3dB with that amp compared to the 2400's. Obviously, it would really be ideal if you had the Titans on one of the 2400's, one cab per amp channel (T48 voltage limit is 60v with the 3015LF). Which, if you're just running one cab per amp channel, you wont need a 20A circuit for. A standard 15 amp circuit will be fine. Depending on your generator, it may (or may not) be enough for both amps. I wouldn't recommend running 2 Titans per amp channel on any of the 2400's unless you have to. The power available into a 4Ω load is less than what the cabs can use. Wouldn't be the end of the world. Just wouldn't be ideal.

Starting with 2 isn't a bad idea. And yes, Titans on the XLS will outperform Tubas on the XLS. I'm not sure what your end game is in this endeavor, but you may just find that 2 is enough. It's likely going to be the equivalent of 10 or more of the Walmart subs you're using now.
Welp, this is the post that did it. After a looooong while lurking and absorbing, I finally registered lol.

P/E is out of stock because I bought the last 4 :lol: Got tired of waiting for LAB 15s for my t48 builds. This Eminence shortage is something serious, so to the OP, I'd grab drivers sooner than later if they're in stock.
Built:
2x Tuba 30x24w (Lab 12)
2x OTop 15 (Kappa 15)
Under Construction:
4x Titan 48x30w (3015LF)
2x OTop 15 (Delta Pro 15)

jakkle21
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Joined: Sat Oct 30, 2021 1:47 pm
Location: Flagstaff AZ

Re: New subwoofer Stack

#11 Post by jakkle21 »

@overdoseonmekka hahahaha, happy to inspire you to also jump in!

My ultimate goal with this project is to have more sound system than I will ever need. I don't want to have to strain any of the gear. I'd like to be able to easily run a main stage at a small (100-300) person event or the small stage at a big (1000+) event, although I've only been to a few events in the last few years so my scale is probably off. I'm not trying to be able run big events, I just don't want the sound system to be the limiting factor. I'd rather invest a bit extra in building it right and learning to run it than have to keep throwing gear at it.

It sounds like 8x T48s as an "ultimate goal" will meet this goal, and that would keep the amp happy at 1 can per channel, per amp, when the full array is needed. With many options for scaling between.

Now what about tops? I have the 4 JBLs right now, so it's not a need, but I'd like to have the whole system run with passive speakers and I really like the efficiency of horns. So with the T48s, are the DR200s plenty of are there compelling reasons to build 250s. Would then xls1500 or the mt1200 be able to run 4 of them?
It sounds like I can sell 2 of my amps, to but speakers and still have plenty of amp to run anything I want.

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Seth
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Re: New subwoofer Stack

#12 Post by Seth »

When it comes to tops, what's personally important to me is keeping size, weight, and cost to a minimum, while also maximizing sensitivity. So, I chose DR200's (I have all the lumber and components, but haven't assembled them yet). Since you don't seem to be worried about size or weight, between the two, I'd recommend DR250's for their superior sensitivity, power handling, and output potential. However... DR's are an intricate, time consuming build. Not necessarily difficult, just time consuming. Lots and lots of parts to craft. The results are worth the effort. However, OmniTop12's will achieve similar output in a cab that's much simpler to construct. Therefore, the OT12 would be my first recommendation. Unless you really really want to build DR's.

Yes, your amps will run them pretty well :thumbsup:

8 T48's would cover a football field handily. Are you familiar with the calculations used to roughly predict predict output over distance? I'm happy to share if you're not.
Last edited by Seth on Tue Aug 16, 2022 7:42 am, edited 2 times in total.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Tom Smit
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Re: New subwoofer Stack

#13 Post by Tom Smit »

One more cab option, for a top, would be the OTop8.
TomS

jakkle21
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Joined: Sat Oct 30, 2021 1:47 pm
Location: Flagstaff AZ

Re: New subwoofer Stack

#14 Post by jakkle21 »

Seth wrote: Mon Aug 15, 2022 9:30 pm 8 T48's would cover a football field handily. Are you familiar with the calculations used to roughly predict predict output over distance? I'm happy to share if you're not.
That sounds perfect, exactly what I want to end up with.
I would love to have the equations, then I can build out some spreadsheets.

I pulled out one of the mt2400s yesterday, and hooked it up to my current subs and it was definitely able to push them noticably louder than the xls. My roommates came over and asked what I did because they could hear way more bass in the house, over 300 feet away. I think 2 T48s will be overkill for normal weekly event, and 4 will cover most anything I'd need them for.

I know the DRs are a lot more complicated than the Otops, but I'm inclined to want to put in the extra work to get a better speaker. But I haven't actually built any speakers yet so I might feel very different after building a few subs. Probably not though, I usually enjoy building things.

Time to sell some gear, contact the specialty wood shop and start looking for components.

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Seth
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Re: New subwoofer Stack

#15 Post by Seth »

Well, there's the down and dirty method and there's the spreadsheet method. Neither is 100% accurate and repeatable in the field due to things that are unaccounted for, such as deployment arrangements, power compression, the effect of bodies in the space, landscape, etc. But, they'll give you a near realistic benchmark and expectation to work with. Here's both methods.



Product marketers will look at these graphs like this and use the highest number and claim that's it's sensitivity. More honest companies tend to average the response sensitivity over the usable frequency range and use that figure as average sensitivity. Personally, I choose the least sensitive figure in the frequency range I expect to reproduce faithfully and base my calculations on that figure. Whether you use 35 or 40Hz is up to you. Most of the time I use 40Hz, because I mostly deal with live music outdoors and 40Hz is the bottom frequency of the frequencies I want to faithfully reproduce and also happens to be the least sensitive point I intend to reproduce.

So, I look at the graph and see the sensitivity of the 36" T48 is about 102dB at 40Hz with 2.83v/1 watt input.

Here's the rough calculations;
Double your power, +3dB
Deploy with a V-Plate, +3dB
The first 100 Watts, +20dB
The first 1000 Watts, +30dB
Double your cab count, +6dB (this is considered +3dB for doubling power and +3dB for doubling the area of the radiating plane (mouth area of a horn loaded cab or speaker cone area of a direct radiating cab) and also assumes the cabs are placed next to each other so that they couple)
Double the distance from the cab, -6dB
Loss over 10 Meters (32.808 feet), -20dB
Loss over 31 Meters (102 Feet), -30dB
Loss over 100 Meters (328.08 feet), -40dB

102dB, plus 20db for the first 100 watts, 122. Plus 3 doubling power to 200, 125. Plus another 3 doubling power again to 400 watts, 128dB (I'm not going to worry about that last 50 watts in this rough calculation. It's only 0.5dB). Double the cab count to two cabs, plus 6, 134dB. Double the cab count again to four cabs, plus 6, 140dB. Add a V-plate, plus 3dB, 143dB at 1 Meter. 33 feet out, minus 20, 123dB. 100 feet out, minus another 10, 113dB. 330 feet out, minus another 10, 103dB.

It's worth noting that due to the way human hearing works, 110dB at 40Hz will only sound as loud as about 90dB at 1kHz. But, it will have impact. Research Equal-loudness contours.

For a spreadsheet, paste this into cell F1
=A1+(LOG(B1*B1)*10)+(LOG(C1)*10)-(LOG((D1/3.2808)*(D1/3.2808))*10)+(IF(ISODD(B1),0,IF(E1="Y",3,IF(E1="N",0))))

Where cell-
A1 is the base sensitivity
B1 is the number of cabs
C1 is power per cab
D1 is distance in feet
E1 is if there is a V-Plate being used, enter Y or N. The formula also automatically disables this option if an odd number of cabs is entered, even if box E1 has a "Y" in it.

Here's how I have mine set up for easy A-B comparisons. In this case comparing four V-Plated 36" T48's on 450 watts each (1800w total) to six JBL SRX728's (Double 18" ported cabs. Twelve 18's altogether) at 1600 watts per cab (9600w total).
Screenshot (203).png
Screenshot (203).png (9.47 KiB) Viewed 590 times

Pop quiz-
- How much power is needed at 40Hz in a 36" wide cab to match the output of the 24" wide cab at 450 watts?
- How many V-Plated 24" T48's at 450w per cab does it take to match or exceed the output potential of four V-Plated 36" T48's with the same power per cab?
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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